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CN-115347210-B - Fuel cell gas diffusion layer and preparation method thereof

CN115347210BCN 115347210 BCN115347210 BCN 115347210BCN-115347210-B

Abstract

The application discloses a fuel cell gas diffusion layer which is suitable for a fuel cell and comprises a porous carbon fiber substrate layer and a microporous layer which are in butt joint, wherein the porous carbon fiber substrate layer is arranged close to a polar plate of the fuel cell, the microporous layer is arranged close to a catalytic layer of the fuel cell, a runner is arranged on one side surface of the porous carbon fiber substrate layer close to the polar plate, the thickness of the porous carbon fiber substrate layer is 100-400 mu m, the depth of the runner is 20-100 mu m, and the thickness of the microporous layer is 20-120 mu m. The application also provides a preparation method of the fuel cell gas diffusion layer. The preparation method of the application is simple, low in production cost and high in production efficiency, and can realize continuous production. The prepared fuel cell gas diffusion layer is applied to a fuel cell, can realize the extremely thin polar plate, and can greatly improve the power density and the cell performance of a fuel cell stack.

Inventors

  • HE FENG
  • QI HE
  • ZHANG ZHEN
  • CHENG JIAO

Assignees

  • 深圳市氢瑞燃料电池科技有限公司

Dates

Publication Date
20260508
Application Date
20220827

Claims (5)

  1. 1. The fuel cell gas diffusion layer is characterized by comprising a porous carbon fiber substrate layer and a microporous layer which are abutted against each other, wherein the porous carbon fiber substrate layer is arranged close to a polar plate of the fuel cell, the microporous layer is arranged close to a catalytic layer of the fuel cell, a flow channel is arranged on one side surface of the porous carbon fiber substrate layer close to the polar plate, the thickness of the porous carbon fiber substrate layer is 100-400 mu m, the depth of the flow channel is 20-100 mu m, and the thickness of the microporous layer is 20-120 mu m; the preparation method of the fuel cell gas diffusion layer comprises the following steps: s01, placing the carbon fiber substrate slurry in a 3D printer for 3D printing to obtain a carbon paper substrate with a runner on one surface; s02, placing the carbon paper substrate in the step S01 into the impregnating solution for impregnating for 1-12 hours, and then drying to obtain carbon paper; s03, performing carbonization and graphitization on the carbon paper in the step S02 after performing hot pressing for 30-240S at 120-200 ℃ and 3-8 MPa to obtain finished carbon paper; s04, carrying out hydrophobic treatment on the finished carbon paper in the step S03, and then carrying out vacuum drying and solidification to obtain a porous carbon fiber substrate layer; S05, arranging a microporous layer on one surface of the porous carbon fiber substrate layer far away from the runner in the step S04 to obtain a fuel cell gas diffusion layer; In the step S01, based on the weight of the carbon fiber substrate slurry being 100%, the carbon fiber substrate slurry contains 1.0% -10.0% of polyacrylonitrile-based carbon fiber, 0.2% -2.5% of organic dispersing agent, 1.0% -3.0% of adhesive and the balance of water; The diameter of the polyacrylonitrile-based carbon fiber is 5-20 mu m, the length is 2-10 mm, and the length-diameter ratio is 200-600; The organic dispersing agent is one or a mixture of at least two of polyacrylamide, polyethyleneimine, anionic starch or cationic starch; The adhesive is one or a mixture of at least two of polyvinyl alcohol, polyethylene oxide, epoxy resin and phenolic resin; In the step S02, the impregnating solution is prepared from water, ethanol and resin, wherein the mass ratio of the water to the ethanol is 1:1-1:3, and the impregnating solution contains 10% -40% of the resin by taking the weight of the impregnating solution as 100%; The resin is phenolic resin or furan resin; in the step S03, the carbonization is performed at 800-1000 ℃ for 15-60 min, and the graphitization is performed at 1500-2500 ℃ for 15-60 min.
  2. 2. The fuel cell gas diffusion layer according to claim 1, wherein the flow channels are serpentine flow channels, parallel flow channels, spiral flow channels or grid flow channels.
  3. 3. The fuel cell gas diffusion layer according to claim 1, wherein in step S02, the drying is performed at 50 ℃ to 90 ℃ for 30min to 120min.
  4. 4. The fuel cell gas diffusion layer according to claim 1, wherein in step S04, the water repellent treatment is performed for 5 hours to 30 hours with a water repellent agent, and the concentration of the water repellent agent is 10% to 50%; the hydrophobic agent is one or a mixture of at least two of polytetrafluoroethylene, polyvinylidene fluoride or fluorinated ethylene propylene.
  5. 5. The fuel cell gas diffusion layer according to claim 1, wherein in step S04, the vacuum drying is performed at 60 ℃ to 100 ℃ for 2 hours to 10 hours, and the curing is performed at 300 ℃ to 400 ℃ for 30 minutes to 5 hours.

Description

Fuel cell gas diffusion layer and preparation method thereof Technical Field The invention relates to the technical field of fuel cells, in particular to a gas diffusion layer of a fuel cell and a preparation method thereof. Background Fuel cells utilize hydrogen energy as the most desirable power generation device. A fuel cell is a power generation device that directly converts chemical energy in fuel into electric energy through an electrochemical reaction. Compared with the traditional energy source, the fuel cell is an efficient and clean electrochemical power generation device, and has recently received widespread attention at home and abroad. At present, commercial fuel cells mainly adopt perfluorosulfonic acid proton exchange membranes, the working temperature is generally not more than 80 ℃, and the defects of poor CO tolerance of a catalyst, the proton conductivity maintenance of a PEM (proton exchange membrane) in a humidifying way, complex cathode water management, the water vapor transmission of a complex flow channel on a polar plate and the like exist. The high temperature proton exchange membrane fuel cell has the advantages of high catalytic activity, high CO tolerance, simple water thermal management and the like because the working temperature is higher than 100 ℃ (usually in the range of 100 ℃ -200 ℃), and can use hydrogen sources such as methanol reformed gas and the like, and water is basically in a gaseous state in a high temperature state, so that the requirements on polar plate flow channel design and gas diffusion layer drainage are reduced, and therefore, the high temperature fuel cell gradually becomes a research hot spot. However, how to solve the problems of high temperature fuel cell reaction gas transmission (such as the concentration difference of gas inlets and outlets) and the great difficulty in processing the polar plate flow channels, and simultaneously reduce the weight of the galvanic pile and improve the volume power density and the mass power density of the galvanic pile is a current research difficulty. Disclosure of Invention Based on the above, the application provides a fuel cell gas diffusion layer and a preparation method thereof, which aim to solve the problems of high processing difficulty of polar plate runners, heavy pile weight, low volume power density and mass power density and the like of the traditional high-temperature fuel cell reaction gas transmission (such as the problem of concentration difference of gas inlets and outlets). According to the application, through optimizing the structure of the gas diffusion layer of the fuel cell, the micro flow channels are arranged on the carbon fiber substrate to realize gas transmission and distribution, so that the difficult problem of great processing difficulty of the polar plate flow channels can be avoided, the problem of reaction gas transmission is solved, and better fuel cell performance is realized. In order to achieve the above purpose, in one aspect, the embodiment of the invention provides a gas diffusion layer of a fuel cell, which is suitable for the fuel cell and comprises a porous carbon fiber substrate layer and a microporous layer which are in butt joint, wherein the porous carbon fiber substrate layer is arranged close to a polar plate of the fuel cell, the microporous layer is arranged close to a catalytic layer of the fuel cell, a runner is arranged on one side surface of the porous carbon fiber substrate layer close to the polar plate, the thickness of the porous carbon fiber substrate layer is 100-400 mu m, the depth of the runner is 20-100 mu m, and the thickness of the microporous layer is 20-120 mu m. The runner is arranged on the porous carbon fiber substrate layer, the gas transmission function required by the original polar plate is transferred to the gas diffusion layer, the processing of the polar plate is simplified, the polar plate is extremely thinned, the quality and the volume of the fuel cell can be greatly reduced, and the power density of the fuel cell is improved. In a preferred embodiment, the flow channel is a serpentine flow channel, a parallel flow channel, a spiral flow channel or a grid flow channel. On the other hand, the embodiment of the application also provides a preparation method of the fuel cell gas diffusion layer, which comprises the following steps: s01, placing the carbon fiber substrate slurry in a 3D printer for 3D printing to obtain a carbon paper substrate with a runner on one surface; s02, placing the carbon paper substrate in the step S01 into the impregnating solution for impregnating for 1-12 hours, and then drying to obtain carbon paper; s03, performing carbonization and graphitization on the carbon paper in the step S02 after performing hot pressing for 30-240S at 120-200 ℃ and 3-8 MPa to obtain finished carbon paper; s04, carrying out hydrophobic treatment on the finished carbon paper in the step S03, and then carrying out vacuum drying and